Adjustable, sealed roll screen for classifying and conveying material-in-process such as taconite pellets

ABSTRACT

A roll screen for conveying and classifying the size of material-in-process such as taconite pellets, having adjustable rollers for changing the sizing of the roll screen and for compensating for wear of the rollers. The rollers are driven from the bottom, therefore individual rollers can be rapidly and easily replaced. The rollers are mounted for rotation in pillow block bearings which are mounted in T-slots on longitudinal bearing plates. The bearings can be loosened and moved longitudinally along the bearing plates. Two sets of overlapping plates or shields which fit into two sets of grooves on the outer and inner edges of the bearing plates prevents the material being classified from migrating into the bearings and seals the bearings against dust. The shields are adjustable in order to accomodate the adjustments of the positions of the rollers. The upper edges of the shields are supported in longitudinal grooved members which are connected to brackets mounted over the bearing plates. The top horizontal portion of a chain guard encloses the tops of the shields, completing the enclosure of the bearings for keeping them clean.

United States Patent 1191 Haley et al.

1451 Nov. 19, 1974 22 Filed: June 22,1973

211 App]. No.: 372,828

[52] US. Cl. 209/106 [51] Int. Cl. B07c H10 [58] Field of Search 209/82, 83, 97, 106, 107

[56] References Cited UNITED STATES PATENTS 2,370,539 2/1945 Hodecker 209/106 2,915,180 12/1959 MacGillivray 2,974,793 3/1961 Kuntz 2,988,781 6/1961 Meyer 3,438,491 4/1969 Haley 20 /l06 Primary Examiner-Richard A. Schacher [5 7] ABSTRACT A roll screen for conveying and classifying the size of material-in-process such as taconite pellets, having adjustable rollers for changing the sizing of the roll screen and for compensating for wear of the rollers. The rollers are driven from the bottom, therefore individual rollers can be rapidly and easily replaced. The rollers are mounted for rotation in pillow block bearings which are mounted in T-slots on longitudinal bearing plates. The bearings can be loosened and moved longitudinally along the bearing plates. Two sets of overlapping plates or shields which fit into two sets of grooves on the outer and inner edges of the bearing plates prevents the material being classified from migrating into the bearings and seals the bearings against dust. The shields are adjustable in order to accomodate the adjustments of the positions of the rollers. The upper edges of the shields are supported in longitudinal grooved members which are connected to brackets mounted over the bearing plates. The top horizontal portion of a chain guard encloses the tops of the shields, completing the enclosure of the bearings for keeping them clean.

6 Claims, 9 Drawing Figures PATENIEL NOV 1 9 I974 SHEEI 10F 3 PATENIE rmv 1 91914 848,741

SHEET 3 OF 3 ADJUSTABLE, SEALED ROLL SCREEN FOR CLASSIFYING AND CONVEYING MATERIAL-IN-PROCESS SUCH AS TACONITE PELLETS FIELD OF THE INVENTION The invention concerns a conveying and classifying apparatus commonly known as a roll screen, having longitudinally adjustable rollers and adjustable shields for sealing from the material being classified the bearings of the rollers.

A representative roll screen, also assigned to Reserve Mining Company, is described in US. Pat. No. 3,438,491. The rollers in the roll screen described in that patent are not adjustable and therefore a change in sizing cannot be made once the apparatus is constructed. In addition, it has been found that the protective covering, such as plastic, on the rollers has to be replaced periodically because of wear. As the rollers wear, the spacing between them becomes greater, which in effect changes the sizing of the apparatus. In an adjustable apparatus the rollers are all merely moved closer together to compensate for wear. Therefore, the rollers have to be replaced or recovered much less frequently. Furthermore, thesizing can be readily changed for use with different materials-in-process.

The roll screen described in this application was developed in a taconite plant. The action of the roll screen spreads the material being classified sideways, forcing material against the seals at the ends of the rolls. If these seals do not fit well at all times, the material will be forced through the seals against and into the bearings. In the past the bearings have been sealed with fixed, non-adjustable seals. In this roll screen the rolls are adjustable so the seals have been made adjustable to accommodate changes in the positions of the rollers.

In addition, the rollers are easier to change than before because they are driven from the bottomof the driven sprockets on the rollers. Previously the sprockets were driven from the top and much of the drive chain had to be removed before changes could be made to the rollers. This was very tedious and timeconsuming. Now even individual rollers can be easily and rapidly adjusted or replaced and the roll and seal easily adjusted to accommodate the change.

SUMMARY The invention comprises a roll screen with adjustable rollers and adjustable shields for sealing the bearings of the rollers from the material being forced toward the ends of the rolls and which normally would spill over into the bearing area. The roll screen includes a frame having longitudinal side members to which solid longitudinal bearing plates are welded or otherwise securely fastened. Each bearing plate has two parallel longitudinal grooves, one along each edge of the plate. Each plate also includes two parallel longitudinal T-slots located between the two grooves. A plurality of rollers is positioned crosswise along the length of the bearing plate. The rollers are mounted for rotation in pillow block bearings which are mounted in the T-slots of the bearing plates. The bearings, and therefore the rollers, can be adjustably positioned along the length of the bearing plates. The bearings are sealed by a plurality of tongued shields having holes for receiving the shafts of the rollers. The shields are arranged in rows, with each of the two sets of bearings positioned between two rows, an inner row and an outer row. Therefore small taconite particles cannot get to the bearings either from the roll screen on the inside or from the area outside the driven sprockets on the rollers. The shields are supported in vertical planes with the bottom edges of the shields held in the grooves along the edges of the bearing plates. Therefore, the bearings are between walls formed by the shields. The upper edges of the shields are held in the grooves in a set of longitudinal stringers connected to supporting hangers mounted over the bearing plates. The roll screen is chain-driven and includes a chain guard. The top portion of the chain guard fits over the tops of the walls formed by the shields so that the bearings of the rollers are completely sealed off from taconite concentrate and dust. The side edges of the shields are tongued so as to make them adjustable to accommodate the side-wise positioning of the rollers when adjustments have to be made thereto.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a top view of the roll screen;

FIG. 2 is a side view of the roll screen FIG. 3 is a sectional view of FIG. 1 from the cutting plane 3-3;

FIG. 4 is a pictorial view of an interior plate for shielding the bearings in the roll screen;

FIG. 5 is a pictorial view of an end plate for shielding the bearings in the roll screen;

FIG. 6 is a pictorial view of a T-nut for fastening the bearings to the bearing plates;

FIG. 7 is a pictorial view of a bracket for supporting the upper edges of the shields shown in FIGS. 4 and 5;

FIG. 8 is a sectional view showing how the shield plates of FIG. 4 are arranged to form walls or barriers DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1, the roll screen includes a frame, F

generally designated by the numeral 10, made up of longitudinal side members 12 and 14 and transverse end members 16 and 18. Fastening means such as studs 20 are used to securely fasten the frame members together.

Longitudinal bearing plates 22 and 24 are welded or otherwise firmly attached to longitudinal side members 12 and 14 respectively. Each bearing plate contains a pair of parallel longitudinal T-slots. The T-slots in bearing plate 22 are referenced with the numerals 26 and 28. The T-slots in bearing plate 24 are referenced with the numerals 30 and 32. The T-slots are so named because of their cross section which is clearly shown in FIG. 3, in which slots 26 and 28 appear as inverted Ts. Not shown in FIG. 1 are two grooves in each of the bearing plates 22 and 24, one along the longitudinal edge of each bearing plate. These grooves are longitudinal and are parallel with the T-slots'. In each bearing plate the T-slots are between the grooves. The grooves are clearly shown in the top surface of bearing plate 22 shown in FIG. 3 and are referenced with the numerals 34 and 36.

A set'of cylindrical elongated rolls or rollers of circular cross section are transversely mounted on frame 10. Two of the rollers are referenced with the numerals 38 and 40. The intermediate portion of each roller has a relatively large diameter compared to that of the end shafts and is covered with a protective covering, e.g., plastic, rubber, or even metal material, which wears with roll screen use so that the distance between roller centers has to be periodically adjusted to keep the same open spacing between adjacent rollers. Eventually the protective coverings have to be replaced.

Each roller has round end shafts of relatively small diameter. Roller 38 has end shafts 42 and 46; roller 40 has end shafts 48 and 44. Shafts 42 and 44 are relatively long compared to shafts 46 and 48. Shafts 42 and 46 are mounted for rotation in bearings 50 and 52, respectively; shafts 48 and 44 are mounted for rotation in bearings 54 and 56, respectively. Bearings 52, 54, and 56 may be of the pillow block type. The rollers are mounted in a staggered pattern and adjacent rollers are driven from opposite sides of the frame. This permits a relatively small spacing between adjacent rollers. Roller 38 is driven from one side of the roll screen by a sprocket 58 keyed on shaft 42 and roller 40 is driven from the other side of the roll screen by a sprocket 60 keyed on shaft 44. Sprocket 58 is driven at the bottom periphery by a chain 62 and sprocket 60 is driven at the bottom periphery by a chain 64. Power is delivered to the roll screen by a drive shaft 70 which is coupled to a power source (not shown). Shaft 70 is rotatably mounted on frame by a pair of takeup bearings 72 and 74 which can be adjusted along the longitudinal dimension of frame 10 to get the proper tension in chains 62 and 64. Sprocket 62 and 68 mounted on the drive shaft at opposite sides of frame 10 drive the chains 62 and 64 which drive the sprockets of rollers. The drive system also includes a set of idler sprockets 76, shown in FIG. 2, and chain guides 78, shown in FIG. 3. Guides 78 hold the chains 64 and 62 in place against the bottom periphery of sprockets 60, 58, etc. Driving the sprockets from the bottom this way makes it easy to adjust and change rollers because the drive chain does not have to be removed as before when the sprockets were driven from the top periphery.

Bearings 50, 52, 54 and 56 are secured to the bearing plates 22 and 24 by bolts and T-nuts, the T-nuts positioned in T-slots 26, 28, 30 and 32. For example, bearing 50 is secured to bearing plate 22 by bolts 80 and 82 as shown in FIG. 1 and T-nuts 84 of the type shown in FIG. 6. The T-nuts ride in the T-slots so that the bearings can be loosened and readily re-positioned along the longitudinal dimension of the roller screen for different sizing or for wear compensation.

Referring to FIG. 3, a set of shield plates 90 and 92, the bottom edges of which are mounted in grooves 36 and 34, protect the bearigs 50, etc., from the material being forced toward the ends of the rolls by the roll screen action. In the past, this taconite concentrate has gotten into the bearings 50, etc. and considerably shortened the useful lives thereof.

An individual shield plate is shown in FIG. 4. The side edges of each plate 90, 92, etc., have tongued side portions 94 and 96 and a hole 98 is located in the central portion of each plate. Referring to FIG. 3, hole 98 is for receiving the shafts of the rollers, for example,

shaft 42 of roller 38 as shown. Note that not all the shield plates require shaft holes. With respect to inner grooves 36, etc., the shafts 42, 48, etc. are spaced twice as close as the shafts that cross over the outer grooves 34, etc. Therefore if the shields are dimensioned for the inner grooves, only about half of the shields for the outer grooves need have shaft holes. In other words, some shields 90, 92, etc. have holes and others are blank. The tongued portions of adjacent shield plates fit into each other and provide a tight, adjustable longitudinal barrier along the sides of the bearings 50, etc. They are adjustable in that the shield plates can be moved longitudinally when the rollers are adjusted, and still provide dust-tight barriers. All the interior shield plates are like that shown in FIG. 4. The exterior or end shield plates 93 are shown in FIG. 5. Eight such end shield plates are required for each roll screen, two for each of four barriers.

Referring to the sectional view of FIG. 8, the shield plate arrangement can be seen. Three adjacent overlapping shield plates a, 90b, and 900 are shown. The tongued portions are dimensioned so that the plates may be moved closer together as the rollers 38, 40, etc., wear and are positioned closer together.

The bottom edges of the shield plates are mounted in the grooves in the bearing plates, for example, referring to FIG. 3, in grooves 36 and 34 of bearing plate 22. The tops of the shield plates are held in place by a set of supports 100, only one of which is shown in FIG. 3. Each support 100 includes a bracket 102, shown in FIG. 7, comprising a vertical member 104, a slotted base member 106 welded to the lower end of member 104 and a horizontal hanger member 108 welded to the upper end of member 104. The slotted base 106 is bolted or otherwise firmly secured to a bearing plate. A pair of longitudinal members, in this case angle-irons 110 and 112, are bolted or otherwise firmly secured to the top portions of bracket 102. As seen in FIG. 7, the top portion of bracket 102 has holes 103 and 105 to receive bolts. Welded to the bottom of angle irons and 112 are stringers 114 and 116 respectively. The bottom surfaces of stringers 114 and 116 have grooves 118 and 120 respectively for holding the upper edges of the shield plates 92 and 90 respectively.

A cover 122 completes the enclosure of the bearings 50, etc. The cross section of cover 122 is an inverted L, the top of which, referenced with the numeral 124, fits over supports 100, the side of which, referenced with the numeral 126, forms a chain guard. The bottom of cover 122 has an inverted V-shaped rim 128 which sits on an extension 130 welded or otherwise secured to frame 12. v

The arrangement of the set of supports 100 is shown more clearly in FIG. 9 which is a sectional view, generally along the line 9-9 in FIG. 3. Sets of plates 90 and 92 are vertically mounted and held in the grooves of stringers 116 and 114.

In summary, an adjustable, taconite concentrate and dust-tight roll screen is provided. The individual rollers can be positioned along the length of the roll screen to compensate for roller wear and to change sizing. Sets of overlapping adjustable. shield plates form dust-tight longitudinal barriers on both sides of the bearings for the rollers. The tops of the barriers are enclosed with a cover which includes a side or skirt forming a guard for the chain guides.

A preferred embodiment of the invention has been shown. Modifications to this embodiment and equivalent embodiments may be developed by persons skilled in the art without departing from the spirit and scope of the invention. Therefore, the invention is to be limited only by the following claims.

What is claimed is:

1. A roll screen, comprising:

a. a frame, including two longitudinal side members;

b. a plurality of spaced rollers mounted for rotation about generally parallel axes;

c. bearings for rotatably mounting said rollers on the side members;

d. means connecting said bearings to the side members for individually adjusting the positions of said rollers along the side members to provide any desired spacing between said rollers to compensate for decreased roller diameter resulting from wear of the rollers and to vary the open area of the roll screen, said connecting means including two longitudinal bearing plates, each with two parallel T- slots therein, said bearing plates attached to the side members;

e. means for mounting said bearings on the bearing plates, said mounting means including T-nuts which move in said T-slots;

f. means for sealing said bearings and said connecting means from foreign material and dust;

g. means for driving said rollers; and

h. means for covering said driving means to guard against accidental interference with the driving means 2. The roll screen of claim 1 in which the longitudinal bearing plates each have two parallel grooves parallel to the T-slots, the T-slots lying between the grooves, and in which the sealing means includes: A plurality of shields for sealing the bearings from material being classified and dust, the lower edges of the shields being inserted in the grooves in the longitudinal bearing plates; means for holding the upper edges of the shield; and means for enclosing the top of the space formed between the shields and containing the bearings.

3. The roll screen of claim 2 in which the side edges of the shields are tongued and are mounted so as to overlap.

4. The roll screen of claim 3 in which the shields have holes for receiving shafts on the ends of the rollers.

5. The roll screen of claim 4 in which the means for holding the upper edges of the shield includes a set of hangers mounted on the longitudinal bearing plates, and longitudinal grooved stringers mounted on the hangers.

6. The roll screen of claim 5 in which the space enclosing means includes a portion of the means for covering the driving means. 

1. A roll screen, comprising: a. a frame, including two longitudinal side members; b. a plurality of spaced rollers mounted for rotation about generally parallel axes; c. bearings for rotatably mounting said rollers on the side members; d. means connecting said bearings to the side members for individually adjusting the positions of said rollers along the side members to provide any desired spacing betweEn said rollers to compensate for decreased roller diameter resulting from wear of the rollers and to vary the open area of the roll screen, said connecting means including two longitudinal bearing plates, each with two parallel T-slots therein, said bearing plates attached to the side members; e. means for mounting said bearings on the bearing plates, said mounting means including T-nuts which move in said T-slots; f. means for sealing said bearings and said connecting means from foreign material and dust; g. means for driving said rollers; and h. means for covering said driving means to guard against accidental interference with the driving means
 2. The roll screen of claim 1 in which the longitudinal bearing plates each have two parallel grooves parallel to the T-slots, the T-slots lying between the grooves, and in which the sealing means includes: A plurality of shields for sealing the bearings from material being classified and dust, the lower edges of the shields being inserted in the grooves in the longitudinal bearing plates; means for holding the upper edges of the shield; and means for enclosing the top of the space formed between the shields and containing the bearings.
 3. The roll screen of claim 2 in which the side edges of the shields are tongued and are mounted so as to overlap.
 4. The roll screen of claim 3 in which the shields have holes for receiving shafts on the ends of the rollers.
 5. The roll screen of claim 4 in which the means for holding the upper edges of the shield includes a set of hangers mounted on the longitudinal bearing plates, and longitudinal grooved stringers mounted on the hangers.
 6. The roll screen of claim 5 in which the space enclosing means includes a portion of the means for covering the driving means. 